No start after running hot.

[ppillard]

I shut the girl down to investigate why she was running hot (fan wasn’t engaging). I lifted the cab to inspect the fan clutch air line, then lowered it to fire her up and build up some air pressure. Now, when I try to start her up, the starter is not even trying to engage. I have DC power, but the starter is not even trying to engage. The display shows a STOP lamp. Is there a lockout engaged that I don’t know about?

 

[SCSG-G4]

What type of vehicle? M1078?

 

[ppillard]

What type of vehicle? M1078?

Yes. Sorry for the lack of clarification.

 

[NDT]

Do you have a voltmeter with you? Is the troublesome thermal switch on the starter bypassed? Look for two small wires that go into a module on the starter not associated with the solenoid. If it's connected still, cut the wires off and twist together. Does the PDP click when you press the red start button? Did you wiggle all your relays and breakers in the PDP?

 

[Suprman]

If you are really running hot then you should let it cool down. You should be able to crank it by jumping the aux start solenoid on the drivers frame rail.

 

[ppillard]

somehow, I got her started. Not really sure what I did. I found a really big crack in my starter, and I’m definitely going to need to replace her. I checked wire connections, tried to hotwire it, and did a lot of head scratching. Then I touched the starter and she fired up.

 

[simp5782]

Where are you located at currently?
Or your intended route to your destination from where you currently are?

 

[NDT]

This problem will resurface. Never drive anywhere in a FMTV without tools and a voltmeter/ohmmeter.

 

[ppillard]

This problem will resurface. Never drive anywhere in a FMTV without tools and a voltmeter/ohmmeter.

I have both. I just lack knowledge of the vehicle.

 

[ppillard]

Where are you located at currently?
Or your intended route to your destination from where you currently are?

Westbound, interstate 30 Texarkana.

 

[NDT]

If the ambient temps are above 40 or so the fan will need to come on. You will need to diagnose this issue. The TM with diagnostic fault tree is located in the TM section of this website.

 

[ppillard]

Is there an ignition lockout regarding cab tilt?

 

[NDT]

No, you can start the engine with the cab tilted. Also to answer an earlier question, when the master warning panel says "stop" that is just a suggestion, there is no electrical interlock. But if you don't you will quickly regret it.

 

[Coffey1]

If the fan is not engaging take air line loose on top of radiator fan shroud bend over to close it and zip tie or tape and fan should be on all the time.

 

[ppillard]

If the fan is not engaging take air line loose on top of radiator fan shroud bend over to close it and zip tie or tape and fan should be on all the time.

That’s what I ended up doing. The fan was working fine until I tried the radIator fan off switch, which worked, but apparently never released. I imagine I need to clean and lube it. Where is the radiator fan override valve?

 

[gringeltaube]

So you are underway again on own power; no longer stranded - or?

 

[Coffey1]

The solenoid that controls the fan in behind passenger kick plate hanging upside down below the relay panel and is most likely cause of fan not working.

 

[ppillard]

switch

So you are underway again on own power; no longer stranded - or?

I managed to get her started again. Not sure why. Starter needs replacement. It is cracked badly where she bolts to the tranny housing. I disconnected and pinched off the air supply to the engine fan to get her cooking again. I managed to limp her the last couple hundred miles to my cousins house, where I’ll replace the starter and clean the radiator fan off valve, which I suspect to be the culprit.

 

[gringeltaube]

So it's not an emergency situation, any longer. Time to update the title, then.



(edited it for you)